Shuttling

In some cases two tankers are used either alternately loading and transporting, or with one tanker aoting as floating storage facility and the other shuttling to and from a shore terminal. 

A substantial fraction of the named enzymes are oxido-reductases, responsible for shuttling electrons along metabolic pathways that reduce carbon dioxide to sugar (in the case of plants), or reduce oxygen to water (in the case of mammals). The oxido-reductases that drive these processes involve a small set of redox active cofactors , that is, small chemical groups that gain or lose electrons. These cofactors include iron porjDhyrins, iron-sulfur clusters and copper complexes as well as organic species that are ET active. 

Beryllium is used as an alloying agent in producing beryllium copper, which is extensively used for springs, electrical contacts, spot-welding electrodes, and non-sparking tools. It is applied as a structural material for high-speed aircraft, missiles, spacecraft, and communication satellites. Other uses include windshield frame, brake discs, support beams, and other structural components of the space shuttle. 

Space Shuttle Space shuttle Columbia Space shuttle orbiter Space shuttle vehicles Space suits Space technology... 

Panels of siUca aerogels have already been flown on several Space Shuttle missions (74). Currently a STARDUST mission has been planned by NASA to use aerogels to capture cometary samples (>1000 particles of >15 micron diameter) and interstellar dust particles... 

Another synthetic strategy is based on self-assembly driven by molecular recognition between complementary TT-donors and 7T-acceptors. Examples include the synthesis of catenanes and rotaxanes that can act as controUable molecular shuttles (6,236). The TT-donors in the shuttles are located in the dumb-beU shaped component of the rotaxane and the 7T-acceptors in the macrocycHc component, or vice versa. The shuttles may be switched by chemical, electrochemical, or photochemical means. 

The practice of employing reusable thermal protection systems for reentry is becoming more common. These are essentially ablative materials exposed to environments where veryHtde ablation actually occurs. Examples iuclude the space shuttle tiles and leading edges, exhaust no22le flaps for advanced engines, and the proposed stmctural surface skin for the National Aerospace plane. 

H. N. KeUey and G. L. SEAh, Assessment of Alternate Thermal Protection Systemsfor the Space Shuttle Orbiter (AIAA/ASME 3rd Joint Thermophysics, Eluids, Plasma and Heat Transfer Conference, June 7—11, 1982, St. Louis, Mo., AIAA-82-0899, 1982. 

C. D. Lutes, Nonlinear Modeling and Initial Condition Estimation for Identifying the Aerothermodynamic Environment of the Space Shuttle Orbiter, Masters thesis. Air Eorce Institute of Technology, WPAPB, Ohio, Jan. 1984. 

C. WiUiams and L. RonquiUo, Thermal Protection System for the Space Shuttle External Tanks, 6th SPI Inti., Tech. /Mark. Conf, 1983, pp. 90—100. 

Conventional extmsion or coextrusion may be performed on vertical or horizontal rotary or shuttle mold configurations. In shuttie blow mol ding the extmder and die are in fixed horizontal and vertical position two or more molds shuttie into and out of position beneath the die. By reciprocating in two planes, the mold may remove a parison and permit the extmder to function continuously. 

This method is slow because of the multiple operations on a shuttle machine. The heat of extmsion sterilizes the bottle, which is not readily achieved after molding. Blow-mold/fill/seal systems are used commercially for beverages and for pharmaceutical packaging. 

Polyimides (PI) were among the eadiest candidates in the field of thermally stable polymers. In addition to high temperature property retention, these materials also exhibit chemical resistance and relative ease of synthesis and use. This has led to numerous innovations in the chemistry of synthesis and cure mechanisms, stmcture variations, and ultimately products and appHcations. Polyimides (qv) are available as films, fibers, enamels or varnishes, adhesives, matrix resins for composites, and mol ding powders. They are used in numerous commercial and military aircraft as stmctural composites, eg, over a ton of polyimide film is presently used on the NASA shuttle orbiter. Work continues on these materials, including the more recent electronic apphcations. 

Solids. Increasing use of bulk cars, especially of covered hopper cars, has accompanied the expansion of the tank-car fleet. The principal drawback of bulk cars is the requirement for limited use, specialized cars, which necessitates a large investment. However, if such investment can be justified, the cost of transportation for dry bulk materials ia hopper cars usually is less than those for goods ia shipping containers. In many instances, such cars are used in closed-loop service that is, they shuttle in unit trains between filling and discharge points. Similar equipment is also used in specialized highway vehicles whose tmck bodies can incorporate dump hoppers and built-in conveyors. 

Sylvinite ore is relatively soft and easily broken. Thus, continuous miners of the boring- or rotating dmm-type can be used. These machines are modified continuous coal miners. This method is used in some of the mines in New Mexico, in all Canadian mines except the solution mines, and in many European mines. Ore is removed from the face by a number of methods, eg, with extensible belt conveyor ore-loading machines and shuttle cars to the main haulage line. To obtain maximum benefits from the continuous miners, the ore transport system must be as nearly continuous as possible. 

The shuttle kiln consists of a firing chamber with two or more kiln cars on which the bricks to be fired are set. While one load of brick is being fired, a second is being set. Somewhat similar is the beU top or top-hat kiln which is raised and lowered above and over the kiln cars to be fired. These kilns are more expensive to operate than tunnel kilns but provide flexibiUty in burning conditions and production schedules. 

In bulk coating processes, bulk materials are joined to the substrate either by a surface melt process or by attachment of the soHd material. An example of the latter is the appHcation of heat-resistant tiles of sHica-type material to the aluminum alloy skin of a space shuttle vehicle, enabling the vehicle to withstand the reentry heat. 

A variety of tiansformation techniques using E. co/ -ye st shuttle vectors and yeast selectable markets, as well as efficient yeast promoters and signal... 

BeryUium is used in the space shuttle orbiter as window frames, umbUical doors, and the navigation base assembly. An important appHcation for beryUium is inertial guidance components for missiles and aircraft. Here the lightweight, high elastic modulus, dimensional stabUity, and the capabUity of being machined to extremely close tolerances are aU important. 

Air Drying Equipment. Tunnel kiln dryers (70) are long furnaces comprised of several zones of different temperature, humidity, and air flow through which the ware travels on a moving car or belt. These kilns afford continuous processing. Periodic kiln cross-circulation dryers (70) are box furnaces in which ware is stacked on permanent racks or on a car that can be shuttled in and out of the furnace. Fans or jets are used to circulate heat uniformly through the ware. The process is not continuous, but production rates can be enhanced by shuttling multiple cars. 

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